This invention relates to the art of insulating devices for building windows and, more particularly, to a thermal barrier mountable interiorly of an existing building window.
It is of course well known to provide an existing building window with an insulating arrangement to reduce heat transfer between the inside and outside of the building through the window and across the junction between the window and its supporting framework. Such insulating arrangements have included, for example, storm windows of wood or metal construction mounted exteriorly of the building window. Such storm windows are not only expensive to manufacture and cumbersome to install, but also are difficult to seal peripherally against leakage between the frame thereof and the building wall or existing window frame. Moreover, if the storm window is of a construction providing sliding window panels, provision for such sliding requires clearance which necessarily creates leakage paths between the frame and the window panels supported thereby. Additionally, such exterior storm windows are exposed to adverse weather conditions including rain, wind and snow and, while they offer protection for the building window from such adverse conditions, they must in turn have sufficient structural integrity to withstand such conditions, thus adding to the size, weight and cost thereof. Efforts have been made to reduce the weight and improve the weather resistance of such storm windows by producing the same from plastic materials, but the latter efforts have not been acceptable for commercial application, and acceptance thereof for residential use has been limited. In any event, such plastic constructions do not avoid air leakage problems and, accordingly, provide no better protection against heat transfer between the inside and outside of a building than do metal or wooden storm windows.
Other efforts heretofore employed to reduce heat transfer, especially in individual homes, have included the covering of a window opening with a thin sheet of flexible plastic material spanning the window opening either interiorly or exteriorly of the existing window. Such a plastic sheet is mounted by taping or stapling the sheet to frame components bounding the window opening, or by rigidly attaching the edges of the sheet material to rigid support members of wood or the like which in turn are nailed or screwed to the window frame components. While such arrangements afford some protection against undesired heat transfer, they are aesthetically unattractive and, if mounted interiorly of the building, do not afford access to the building window, such as for cleaning the latter, without physically damaging the sheet material and/or the window framing by removal of the plastic sheet from the window framing. Moreover, the side of the plastic sheet material facing outwardly toward the existing window cannot be cleaned without removal of the sheet from the window frame and, if the plastic is left uncleaned so as to prevent damage thereto and/or to the window framing, this further detracts from the aesthetic value of the interior of the building. Still further, window framing is often out of square, whereby it is practically impossible to avoid wrinkling of the plastic material, and such wrinkling of course further detracts from the desired appearance of the interior of the building.